"I feel awesome," said Chapman, who turns 40 early next month. "This is one more check-off on the list of my goals."
The win was his fourth B.A.S.S. victory, although it was his first Elite Series win.
Starting at 11th place on Thursday, then jumping up to lead for the next two days, Chapman weighed in 23 pounds, 11 ounces of bass today to boost his four-day total to 83-9 - a margin of victory of 4 pounds, 4 ounces over Cliff Pace of Mississippi., who tallied 79-5 for second place.
South Carolina's Marty Robinson ended the event in third with 77-11, while Gonzales' Greg Hackney turned in a fourth-place performance with 76-1. Fifth was rookie Cliff Prince of Palatka, Fla., who had 69-9.
Click here for complete standings.
In addition to a thicker pocketbook, Chapman also earned an automatic berth in the 2013 Bassmaster Classic and took over the Bassmaster Angler of the Year points race.
The Classic qualification was his second of the season; the first one came by winning the Bassmaster Central Open event on Lake Lewisville in February. Because he already had the 2013 Classic entry sewn up, it was the Elite victory that made his day.
He was never sure he had the win until the scales stopped moving on his Sunday bag.
"I truly felt I needed 20 pounds today to have a shot at winning this," he said. "I had a lot more than I thought I did."
The Sunday scales settled on 23-11, with a spoon being the key to his four days of success. The icing on the weight was a last-hour bass that almost offered itself to him.
"I throw my spoon out, go to reel it in, and I see the spoon at about 5 feet from the boat - and a 4-pounder is behind it," Chapman explained. "I killed the spoon - kind of dropped it - and the bass sucked it in. I just whipped it into the boat.
"When stuff like that happens, I think, 'Maybe I am supposed to win this deal.'"
Throughout the week, the winner's focus went much deeper. He worked several spots, but particularly one area that held schools of big bass 25 to 30 feet deep. He used a 5-inch, 1 1/4-ounce flutter spoon with a silver finish modified with a 2/0 Lazer TroKar treble, or worked a Tightlines green-pumpkin UV Hog on a 3/4-ounce football jig.
The spoon was a lure he picked up at a tackle store, and it had no brand name, Chapman said. A lover of fishing banks and shallows, Chapman steeled himself to going deep during the Toledo Bend Battle, and turned to the spoon to help him.
"It's a thing that Kelly Jordan made famous, and it's a bait I've really fallen in love with over the past few years when it comes to this time of year and fishing deep," he said.
Chapman had declared after Day 3 that in the final round, he would not live and die on the same spot he'd worked all week.
Come later Sunday morning, he was ready to move, he said, but the bass changed his mind: He caught a 5-pounder and then a 6-7, his largest of the day and also the day's big bass in a tie with the 6-7 brought in by Greg Hackney.
Then Chapman moved off his spot, but later returned for another dip. No go.
"When it dries up, it dries up in a hurry," he said.
Through Sunday's win, Chapman earned enough points to recover his early-season lead in the Bassmaster Angler of the Year points race. The closest he's ever come to the AOY title is eighth in 2007.
But with three more Elite events remaining in the regular season, Chapman said he's not obsessing over the crown. He's not centering his fishing strategy on winning the AOY prize.
"Angler of the Year, I've got to keep off my mind until the last day at Oneida (the season's final event)," Chapman said. "You've got to focus on one fish at a time, one day at a time, one tournament at a time."
Mississippi's Pace pulled up to finish in second place after leading the first day, and then dropping to fourth by Day 3. His Sunday catch of 21-9 revived his bid for his first Elite win, but in the end fell short.
"Anytime you get to fish all four days, you've had a great week," Pace said. "Second place is a great tournament. A win would have been much better, but that's just part of life. Brent had better group of fish found, and he beat me."
Pace's strategy was to work deep schools slowly and thoroughly.
"That was the whole deal for me," he said.
He made long casts with a 3 1/4-ounce V&M football jig, and spent about three minutes dragging it back to the boat each time.
When the wind died, he turned to a Carolina rig with a redbug V&M Super Finesse Worm, same slow technique.
"When I say drag it, I mean at a snail's pace," Pace said.
Like Chapman, South Carolina's Robinson started slowly on Day 1. He bagged a modest 15 1/2 pounds, good enough for 23rd place.
Then on Day 2, armed with a 21-12 bag, he fought his way up into sixth place. The third day was almost a cookie-cutter of the second: 21-5, but it did him even more good.
He advanced to second place, just 1 pound, 5 ounces behind leader Chapman.
The final day Robinson pushed hard, finishing third, the best showing of his Elite career. He bagged 19-2, ending almost 6 pounds behind the winner.
"I just didn't get a lot of big bites today," he said. "I had one place where I had caught some big fish, but I couldn't get him fired up."
Robinson used a ¾-ounce peanut-butter-and-jelly Buckeye Mop Football jig and a Fish Stalker Lures' Party Marty football jig with a Zoom Critter Craw.